The prior art process for making a rubber-like product from recycled tire rubber, or rubber scrap, is described in U.S. Pat. No. 2,809,944, issued Oct. 15, 1957.
Related patents include U.S. Pat. Nos. 1,550,968, issued Aug, 25, 1925; 4,073,753, issued Feb. 14, 1978; 4,097,644, issued June 27, 1978; 4,250,222, issued Feb. 10, 1981; 4,506,034, issued Mar. 19, 1985 and Canadian Pat. No. 687,455, issued May 26, 1964.
The prior art process of producing a rubberlike product from rubber scrap includes mixing rubber scrap with from 2 percent to 20 percent with respect to the weight of the rubber scrap of added sulphur, and applying a working and plasticizing action at a temperature of from about 300 degrees F. to about 500 degrees F.
A problem with the prior art process is the difficulty in applying a working and plasticizing action by using a screw impeller plasticizer or the like.